Synonyms of certain
16 similar words · 4 opposite words
Another word for certain is sure. Other synonyms of certain are positive, doubtless, sicker, unwavering and unambiguous. The opposite of certain is uncertain.
Synonyms and similar words for certain
adjectiveSure to happen, inevitable; assured.
adjectiveNamed but not previously mentioned.
pronounUnnamed or undescribed members (of).
- someA certain number (multiple but not all).
adjectiveMore synonyms
- assured
- clear
- confident
- definite
- doubtlessCharacterized by or experiencing no doubt at all, certain; undoubted; undoubting.
- positiveFully assured in opinion.
- sickerCertain.
- surePhysically secure and certain, non-failing, reliable.
- unambiguousClear, and having no uncertainty or ambiguity.
- unequivocal
- univocalHaving always the same drift or tenor; uniform; certain; regular.
- unwaveringNot doubting or unsure; decisive, firm, resolute.
- wisCertain.
Opposite of certain
adjectiveAntonym(s) of “not doubting”.
- uncertainNot certain; unsure.
adjectiveAntonym(s) of “sure to happen”.
adjectiveAntonym(s) of “known but not named”.
- particular specific
Meaning of certain
- adjective Sure in one's mind, positive; absolutely confident in the truth of something.
- adjective Not to be doubted or denied; established as a fact.
- adjective Sure to happen, inevitable; assured.
certain in other languages
Questions about synonyms of certain
- What is another word for certain?
- Certain has 16 synonyms on Word.ws, such as sure, positive, doubtless, sicker, unwavering, unambiguous and clear.
- What is the opposite of certain?
- The opposite of certain is uncertain.
- What does certain mean?
- Certain means sure in one's mind, positive; absolutely confident in the truth of something.
Source and license
Adapted from Wiktionary: certain (page history and authors) and the entries of the words listed. Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws grouped the synonyms and antonyms by meaning and added links. Wiktionary data of 2026-09-02.
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Cite this page: “Synonyms of certain.” Word.ws, https://word.ws/synonyms/certain. Based on Wiktionary, CC BY-SA 4.0.